Plastic drill pipes and sucker rods for oil wells



Oct. 19, 1965 K. D. BROWN 3,212,582

PLASTIC DRILL PIPES AND SUCKER RODS FOR OIL WELLS Filed Feb. 9, 1959 INVENTOR, /Ww ,Q ia/4W United States Patent O 3,212,582 PLASTIC DRILL PIPES AND SUC'KER RODS FOR OIL WELLS Kenard D. Brown, Fort Collins, Colo. (1227 S. Willow St., Casper, Wyo.) Filed Feb. 9, 1959, Ser. No. 792,143 7 Claims. (Cl. 166-242) This invention relates to an improved sucker rod and tubing structure for oil wells, more particularly for use on wells being pumped by a standard rig employing a pumping jack on the surface which acts to vertically reciprocate a sucker rod for actuating a subsurface pump to elevate the oil within a string of tubing surrounding the sucker rod.

In pumping high paraffin base oils with this type of standard equipment, the paraffin rapidly collects and builds upon both the sucker rod and the tubing so to quickly reduce the output of the well. When this occurs, the sucker rod and the tubing must be withdrawn and disjointed to remove the paraffin deposits. This is an expensive and time consuming procedure.

The principal object of this invention is to provide a sucker rod and tubing structure of a type which will prevent the depositing and accumulation of paraffin and to provide a sucker rod and tubing structure which will allow the sucker rod and the tubing to be withdrawn from the well in a continuous length so as to completely eliminate the expensive, time consuming jointing and disjointing of the conventional sectional sucker rod and tubing.

It has been found that paraffin has an affinity for metal parts. It will rapidly and rmly attach to and build up upon all exposed metal surfaces submerged in the oil in the well. Experiment has shown, however, that paraflin will freely flow over synthetic plastic surfaces without attachment or accumulation. This improved sucker rod and tubing structure completely eliminates all exposed metallic surfaces for the accumulation of parafiin by forming both the sucker rod and the tubing from metal reinforced, flexible plastic so constructed that the metal parts are completely insulated from the oil by the plastic and so constructed that the tubing and the rod will be continuous, flexible units throughout their entire lengths so that they can be withdrawn from the well -as units without disjointing and so that both may be reeled upon a reel as they are withdrawn for cleaning, replacements, and repairs.

Other objects and advantages reside in the detail construction of the invention, which is designed for simplicity, economy, and eiciency. These will become more apparent from the following description.

In the following detailed description of the invention, reference is had to the accompanying drawing which forms a part hereof. Like numerals refer to like parts in all views of the drawing and throughout the description.

In the drawing:

FIG. 1 is a side view of one extremity of the improved tubing and sucker rod, the wall layers thereof being broken away in succession to show the internal construction;

FIG. 2 is a cross section through the sucker rod and tubing structure of FIG. l;

FIG. 3 is a similar successively broken away side view of an alternate form of the improved sucker rod and tubing structure; and

FIG. 4 is a cross section through the alternate form of FIG. 3.

The sucker rod of the preferred form comprises a plurality of relatively straight, longitudinally extending, spaced, exible steel rod wires completely embedded ICC in a cylindrical, plastic rod 11. The tubing of the preferred form comprises an annular plurality of similar relatively straight steel tension wires 12 embedded in a tubular, plastic, cylinder between an outer plastic shell 13 and an inner, separating layer of plastic 14. The inner, separating layer of plastic 14 surrounds a tubular helically wound core wire 15 which in turn surrounds an inner tubular plastic lining 16.

For the purpose of illustrating the wall structure of the tubing the latter has been illustrated in FIG. 1 as being cut away successively at increasing depths. It could be formed by wrapping the helical core wire 15 about the tubular plastic lining 16 thence placing the layer 14 thereover as a continuous tube, thence placing the tension wires 12 along the latter tube and covering them with the outer shell 13. For quantity production, however, the entire structure could be extruded simultaneously about the wires so that a unitary tubular plastic cylinder would include and enclose the inner helical core wire 15 and the outer tension wires 12. The tubing structure could be extruded from the plastic die simultaneously with the wires 10 and the plastic covering 11 of the sucker rod so that the tubing and the rod could be formed simultaneously.

In use, the above described tubing structure is run into the well as a continuous unit and the above described sucker rod, connected to the pump, is similarly, either individually or simultaneously, run into the well as a continuous full length unit. The pumping is accomplished as usual, by applying tension to the sucker rod through the medium of a pumping jack with the oil flowing upwardly between the plastic surface of the sucker rod and the plastic lining of the tubing. It will be noted that no metal is exposed to the oil so that the accumulation of paraffin is substantially eliminated.

It will also be noted that since both the tubing and the sucker rod are formed in continuous, unitary, exible lengths, both can be unreeled from a reel at the surface as they are run into the well and re-reeled so as to eliminate all jointing and disjointing steps. p

The form of FIGS. 3 and 4 is similar to that previously described. However, in the second form, tension wires 17, exposed on the exterior of the tubing, are wrapped about a plastic separating cylinder 18 in a continuous spiral. The tubing 18 contains a spiral core wire wrapping 19, similar to the wrapping 15 previously described, and a lining tube 20, similar to the tube 16 previously described. The sucker rod of the second form, indicated at 21, is a cylindrical, plastic rod containing longitudinally extending reinforcing wires 22 similar to the elements 10 and 11 previously described. The advantages, the functions, and the use of the second form is similar to that of the previously described form.

Sucker rods are exposed to tensional strains due to the weight of the oil and the rod itself. They are also exposed to bending stresses and wall friction due to misalignment of the well. This improved sucker rod is ideally suited to meet these conditions since the straight wires 10 easily absorb the tension and, due to their individually small diameters, they absorb the bending stresses with much less effort than a solid rod. The oil lubricated plastic surfaces of the rod and tubing have a relatively low coetiicient of friction so that ease of operation with minimum wear results.

It can be seen that the improved rod and tubing structure will greatly increase the efiiciency of pumping, in that paraffin shut-downs are greatly reduced if not completely eliminated; full ow is maintained; and the time and labor of pulling is reduced to a minimum.

The core wires 15 and 19 have been illustrated as a single wire wound in spaced-apart turns. It could, of

course, be a plurality of wires wound simultaneously in side by side relation and the spacing could vary in accordance with the particular pressures and conditions which the tubing is designed to accommodate.

The tension wires 12 have been illustrated as straight and the tension wires 17 are positioned at an incline to the axis. These tension wires could, of course, be positioned at any desired incline intermediate the positions shown in FIG. 1 and FIG. 3 depending upon the service for which the tubing is being designed.

The plastic used in the sticker rod and tubing may be any suitable type such as the alkyd resin plastics, commonly known as the polyethylenes or the vinyl plastics, commonly known as vinylidene chloride plastic.

While a specific form of the improvement has been described and illustrated herein, it is to be understood that the same may be varied within the scope of the appended claims, without departing from the spirit of the invention.

Having thus described the invention What is claimed and desired secured by Letters Patent is:

1. A unitary tubing and rod assembly for oil well pumping and the like comprising an extended length of flexible tubing having a coextensive length of flexible rod therein, said rod having a cross section substantially less than that of the tube passage to leave a free passage for the ow of fluid through said tube, said tube comprising a plastic wall and having a continuous smooth plastic interior Wall surface, a helically wound core wire embedded in the plastic of the wall of said tube and spaced from said interior wall surface, a tension wire secured to said tube outside said passage and extending the length of said assembly, said rod being constructed of plastic and having a continuous smooth plastic exterior wall surface, and a rod tension wire spaced inwardly of said rod surface and embedded in and extending longitudinally the length of said rod, the flexibility of said assembly being sufficient to enable it to be wound on a drum or the like and moved as a unit into and out of a well.

2. A tubing and rod assembly as described in claim 1 in which the tube tension wire is also embedded in the plastic forming the wall of said tube.

3. A tubing and rod assembly as described in claim 2 in which both the core wire and the tension wire are inclined at an angle to the axis of said tube.

4. A continuous fluid conducting and tension load carrying tubing for conveying oil and the like comprising: an elongated, flexible synthetic resin plastic tube having a continuous smooth inner wall surface; a helically wound core Wire completely embedded in the wall of said tube in proximity to but spaced from the inner wall surface of said tube; and a straight tension wire extending in a generally axial direction along said tube and completely embedded in the wall thereof exteriorly of and separated from said core wire.

5. A sucker rod for pumping oil wells comprising: a solid elongated rod of flexible plastic having a multiplicity of longitudinally extending tension wires spaced from one another and distributed throughout the cross section of the rod and each being embedded in and completely surrounded by the plastic forming said rod.

6. An elongated tension member for use with equipment lowered into and withdrawn from oil wells and the like comprising a continuous elongated body of flexible synthetic plastic presenting a continuous smooth exposed plastic surface throughout its length and a multiplicity of substantially uniformly spaced straight tension wires extending longitudinally and continuously through said body and completely embedded therein and reinforcing said plastic body to maintain its configuration under tension.

7. In combination, a tubing and sucker rod for oil well pumping and the like comprising a unitary assembly including a flexible tubing having a continuous smooth internal wall surface of synthetic plastic, and a exible sucker rod having a continuous smooth external surface of synthetic plastic and positioned within said tubing, said rod having a cross section substantially less than the bore of said tubing to leave a free passage for the flow of uid, said rod and said tubing being substantially coextensive in length whereby all contacting surfaces of said rod and tubing are of synthetic plastic and have low friction between said surfaces, the flexibility of said rod and tubing and said low friction facilitating the reeling of said assembly in and out of a well as a unit, reinforcing wires for said tubing spaced radially outwardly from said plastic internal wall surface and protected by the inner wall from uids within said tubing, and reinforcing tension wires for said sucker rod arranged within and protected by the plastic wall surface thereof.

References Cited by the Examiner UNITED STATES PATENTS 617,770 1/99 Purdy 166-243 1,183,631 5/16 Clark 103--155 1,189,516 7/16 Whitney 166-46 2,448,485 8/48 Chernack 138-133 2,453,079 ll/48 Rossmann.

2,564,602 8/51 Hurst 138-125 2,593,714 4/52 Robinson 154-83 2,670,762 3/54 Stivason et al. 138-56 2,690,769 10/54 Brown 138-125 2,762,436 9/56 Brown 166-46 2,773,671 12/56 Leibensperger.

2,787,917 4/57 Schroeder.

2,821,092 l/5 8 Cordora et al.

2,825,364 3/58 Cullen et al 13S-56 2,871,718 2/59 Schroeder.

2,877,150 3/59 Wilson 154-83 2,879,803 3/59 Francois 138-56 2,997,120 8/61 Kendrick 175-103 BENJAMIN HERSH, Primary Examiner.

BENJAMIN BENDETT, CHARLES E. OCONNELL,

Examiners. 

4. A CONTINUOUS FLUID CONDUCTING AND TENSION LOAD CARRYING TUBING FOR CONVEYING OIL AND THE LIKE COMPRISING; AN ELONGATED FLEXIBLE SYNTHETIC RESIN PLASTIC TUBE HAVING A CONTINUOUS SMOOTH INNER WALL SURFACE; A HELICALLY WOUND CORE WIRE COMPLETELY EMBEDDED IN TEH WALL OF SAID TUBE IN PROXIMITY TO BUT SPACED FROM THE INNER WLL SURFACE OF SAID TUBE; AND A STRAIGHT TENSION WIRE EXTENDING IN A GENERALLY AXIAL DIRECTION ALONG SAID TUBE AND COMPLETELY EMBEDDED IN THE WALL THEREOF EXTERIORLY OF AND SEPARATED FROM SAID CORE WIRE.
 5. A SUCKER ROD FOR PUMPING OIL WELLS COMPRISING: A SOLID ELONGATED ROD OF FLEXIBLE PLASTIC HAVING A MULTIPLICITY OF LONGITUDINALLY EXTENDING TENSION WIRE SPACED FROM ONE ANOTHER AND DISTRIBUTED THROUGHOUT THE CROSS SECITON OF THE ROD AND EACH BEING EMBEDDED IN AND COMPLETELY SURROUNDED BY THE PLASTIC FORMING SAID ROD. 